There are several autoimmune disorders that cause it, but if none test positive, ask whether you are short of glutathione? Made by the liver, it helps all kinds of things and chronically low, it causes falling (plus foggy brain, low energy). Milk thistle boosts liver and is KEY—(available in capsules), as does NAC, if you’re short of any of the three ingredients. To make glutathione, the liver needs sulfer (greens, dried peaches or apricots treated with sulfer, eggs, garlic, onions) plus vitamin C, plus selenium (meats & cheese). Spinach and avocado have small amounts of glutathione. Taking glutathione in pills may work, but it’s expensive. It took me a long time to figure out, but look it up and try to get the ingredients into your diet. Read about it for clues. (No doctor is likely to suggest glutathione, or help, even if you suggest it. I asked dozens, including neurologists.) I fell for years until I started putting it together. Good luck! (even if you have one of the major diseases, glutathione may still be a problem and make them worse, so study it along with anything doctors suggest.